A compound event involves measuring the probability of more than one event in a row. In order to find that probability, you have to multiply the probabilities of each of the single events together. That product is the probability of the compound event.
For example, if you want to know the likelihood of flipping a coin four times in a row and getting heads every time, you have to multiply the probabilities for each of the four coin flips.
1 ⁄ 2 · 1 ⁄ 2 · 1 ⁄ 2 · 1 ⁄ 2 = 1 ⁄ 16
This means there is a 1 in 16 chance of getting heads in four coin tosses in a row.
James is flipping a coin twice. He says the probability that he’ll get tails both times is 1/2. Which of these is true?
A
James is right. The probability that he’ll get tails both times is 1/2.
B
James is wrong. The probability that he’ll get tails both times is 2/1.
C
James is wrong. There is no chance (0%) that he’ll get tails both times.
D
James is wrong. The probability that he’ll get tails both times is 1/4.
D
James is wrong. The probability that he’ll get tails both times is 1/4.
To find the probability of getting tails on both coin flips, you have to multiply the probability of getting tails on the first flip (1/2) by the probability of getting tails on the second flip (1/2).
1/2 * 1/2 = 1/4
Therefore, the correct probability of getting tails both times is 1/4, not 1/2.